An electric discharge machining apparatus of the wire-cutting type for machining a work piece by utilizing an electric discharge between a wire electrode and the work piece to be machined in known. In general, the conventional electric discharge machining apparatus of the wire-cutting type comprises an upper wire guide member for guiding a wire electrode above a work table for holding a work piece thereon and a lower wire guide member for guiding the wire electrode below the work table. For the electric discharge machining operation, the wire elect rode is tightly string between the upper wire gude member and the lower wire gude member, and the wire electode is continuously fed downward by a wire feed device arranged above the upper wire guide member. In this conventional electric deischarge machining apparatus of the wire-cutting type, where it is necessary to change the electric discharge machining position, the wire electrode must be once cut between the upper and lower wire guide members and the wire electrode automatically string between the upper and lower wire guide members again. Furthermore, where the wire electrode is broken in the discharge region by abnormal electric dischargeing or the like, the broken end of the wire electrode must be pulled up from the discharge region, the readily bending portion or the surface-roughened portion of the wire electrode cut out, and the wire electrode then automatically string between the upper wire guide member and the lower wire guide member. Accordingly, in the conventional electric discharge machining apparatus of the wire-cutting type, a wire-cutting device is disposed above or below the upper wire guide member.
In the conventional electric discharge machining apparatus of the wire-cutting type in which the wire-cutting device is disposed above the upper wire guide member, the lower end, that is, the free end, of the cut wire electrode is fed downward by the wire feed device. The free end of the wire electrode is readily caught in narrow wire passages of the upper and lower wire guide members or in holes or grooves of the work piece, and therefore, it is difficult to perform automatic stringing of the wire electrode accurately In the electric discharge machining apparatus of the wire-cutting type in which the wire-cutting device is disposed below the upper wire guide member, it is difficult to smoothly pass the free end of the wire electrode through the holes or grooves of the work piece or the narrow passage of the lower wire guide member.